<template>
    <div>
        <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
            <span class="iconfont header-abs-back">&#xe601;</span>
        </router-link>
        <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
            景点详情
            <router-link to="/">
                <div class="iconfont header-fixed-back">&#xe601;</div>
            </router-link>
        </div>
    </div>   
</template>
<script>
export default {
    name:'DetailHeader',
    data(){
        return{
            showAbs:true,
            opacityStyle:{
                opacity:0
            }
        }
    },
    methods:{
        handleScroll(){
            const top = document.documentElement.scrollTop
            if(top > 60){
                const opacity = top / 140
                this.opacityStyle = {
                    opacity
                }
                this.showAbs = false
            }else{
                this.showAbs = true
            }
        }
    },
    created(){
         window.addEventListener('scroll',this.handleScroll)
    },
    deactivated(){
        window.removeEventListener('scroll',this.handleScroll)
    }
}
</script>
<style lang="stylus" scoped>
    @import '~styles/varibles.styl'
    .header-abs
        position absolute 
        left .2rem 
        top .2rem 
        width .6rem 
        height .6rem 
        border-radius .4rem
        text-align center 
        line-height .6rem
        background rgba(0,0,0,.8)
        .header-abs-back
            color #fff
            font-size .3rem
    .header-fixed 
        z-index 2
        position: fixed
        top 0 
        right 0
        left 0
        height $headerHeight
        line-height $headerHeight
        text-align center
        color #fff
        background  $bgColor
        .header-fixed-back
            position absolute
            top 0
            left 0
            width :.64rem
            text-align center 
            font-size .4rem 
</style> 